Devices for providing acoustic hemostasis

ABSTRACT

Methods and apparatus for the remote coagulation of blood using high-intensity focused ultrasound (HIFU) are provided. A remote hemostasis method comprises identifying a site of internal bleeding and focusing therapeutic ultrasound energy on the site, the energy being focused through an intervening tissue. An apparatus for producing remote hemostasis comprises a focused therapeutic ultrasound radiating surface and a sensor for identifying a site of internal bleeding, with a registration means coupled to the radiating surface and the sensor to bring a focal target and the bleeding site into alignment. The sensor generally comprises a Doppler imaging display. Hemostasis enhancing agents may be introduced to the site for actuation by the ultrasound energy.

This application is a regular utility application claiming the benefitof the filing date of Provisional U.S.patent application Ser. No,60/000,813, filed Jun. 23, 1995. This application is also aContinuation-In-Part of U.S. Ser. No. 08/446,503, filed May 22, 1995,now U.S. Pat. No. 5,762,066.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the remote application oftherapeutic radiated energy. In particular, the present inventionprovides a method for applying High Intensity Focused Ultrasound toreduce internal bleeding.

The use of ultrasound for imaging and diagnosis of disease is well knownin the medical field. Ultrasound imaging generally relies on differencesin the reflection of high frequency acoustic waves by organs and softtissues. Ultrasound waves, when applied at power levels required forimaging, have been found to be free from the deleterious side effectsassociated with many other forms of radiated energy, such as X-rays,microwaves, and other electromagnetic fields. Hence, ultrasound imagingsystems have a distinct safety advantage over other known imagingmodalities.

Generally, imaging ultrasound waves are radiated from a transducer whichalso senses the reflections. Imaging ultrasound transducers often makeuse of multiple radiating and/or receiving surfaces. For example, modernultrasound probes often use precise timing control over a series ofactive surface regions, referred to as a phased array, to control theradiation direction and to sense the source of reflections. Ultrasoundimaging systems having multiple transducer surface regions have foundparticular use in Doppler measurements of internal blood flows.

Ultrasound Doppler imaging systems make use of multiple ultrasoundpulses to non-invasively monitor internal movements. Doppler imagingtypically relies on the frequency shift of acoustic reflections frommoving matter, and also on the change in position of discrete massesbetween pulses. Doppler colorflow imaging indicates relative speeds ofmotion by assigning a range of false colors for the measured speeds.Ultrasound Doppler systems may scan a single sector of tissue, or mayscan in multiple orientations to provide three-dimensional imaging.Array transducers facilitate Doppler imaging by providing electronicscanning through control of the phase of excitation provided to thediscrete regions of the array.

Although ultrasound imaging is noted for its safety, ultrasound energyapplied at higher power densities can have significant physiologicaleffects on tissues. These physiological effects may result from eitherthermal or mechanical effects of ultrasound energy. Thermal effects ofultrasound include localized heating, hyperthermia, and ablation oftissue (with relatively low energy levels), and even rapid hightemperature searing. Mechanical effects include breaking-up of solidobjects, liquefaction of tissues, and cavitation.

These effects of high power ultrasound can occur adjacent to theultrasound radiating surface, or they may be produced at a distance fromthe radiating surface by focusing of the ultrasonic waves at a targetregion within the tissue. For example, lithotriptors use a largeexternal radiating surface to focus short bursts of ultrasound energy asshock waves inside a patient body, thereby mechanically fragmentingkidney stones. Clearly, the ultrasound energy must be focused on atarget region which is very small relative to the transmitting surfaceto avoid affecting the intermediate tissue.

The use of High Intensity Focused Ultrasound (herein referred to as"HIFU") has previously been proposed as a therapy for a number ofdiseases which manifest themselves in a localized or "focal" manner.Focal diseases for which HIFU has been suggested include, for example,neoplastic and other diseases of or in the brain, breast, liver, andprostate. Although surgical procedures have been developed for thesediseases, HIFU therapy potentially offers a non-invasive or minimallyinvasive alternative, thereby inflicting much less trauma on thepatient, and promoting faster healing. For example, HIFU therapy is nowavailable as a treatment for Benign Prostatic Hyperplasia, allowing theremote ablation of hyperplastic tissue without physical penetration ofthe urethra and prostate, thus reducing the risk of infection.

U.S. application Ser. No. 08/446,503, the full disclosure of which isherein incorporated by reference, describes an exemplary HIFU system andmethod for the treatment of BPH and other focal diseases. This exemplaryHIFU system includes a probe housing containing a multifacetedtherapeutic transducer member and a servo system for aiming thetransducer member within the probe. The transducer member has aplurality of radiating surfaces having different focal lengths anddifferent radial orientations. Power is transmitted to alternativeradiating surfaces to select a target depth. Additionally, anindependent inner region of each radiating surface allows furthervariation in the target depth by manipulating the inner region's powersupply phase relative to the surrounding outer region, the inner andouter regions acting as a simple phased array. An imaging transducer isalso carried on the transducer member, allowing a single servo system toselect the focal depth, aim the therapeutic surface, and scan theimaging transducer.

Although the above described HIFU system and probe have proven highlyeffective as a tool for applying HIFU therapy to focal diseases, theHIFU methods and systems proposed to date suffer from certainlimitations. Specifically, HIFU treatments have generally relied only onthe thermal and mechanical effects of ultrasound energy on fixed tissuesand structures. The potential application of therapeutic ultrasoundenergy on body fluids, particularly for the coagulation of blood tocontrol internal bleeding, has not previously been explored.

One of the most common causes of the death of trauma victims, bothmilitary and civilian, is internal bleeding. Broadscale internalbleeding is difficult to detect, has few well-recognizable symptoms, andcan lead to death within a time ranging between minutes and severaldays. Blunt trauma often leads to hemoperitoneum from a rupture of theblood supply system of the abdominal organs and tissues, thus causingleakage of blood into the abdominal cavity and surrounding tissues. Theorgans most commonly injured include the liver, spleen, and kidneys. Thesurvival rates from trauma victims with hemoperitoneum has been found toincrease dramatically when proper care is provided soon after theinjury.

The survival rate of trauma victims who survive long enough to receivestate-of-the-art medical care at a major medical facility is relativelygood. Once at such a facility, intra-abdominal fluid is often detectedusing Diagnostic Peritoneal Lavage (DPL). DPL is an invasive procedurehaving a complication rate of as high as 5%, typically from bowel orbladder perforation. Although ultrasound Doppler imaging offers anon-invasive diagnostic alternative, invasive therapies are generallyrequired after diagnosis to control any significant internal bleeding.

Unfortunately, facilities capable of invasive surgical procedures,including DPL and abdominal surgery, are often a considerable distancefrom the injury site, requiring considerable transportation time.Additional time after arrival at a surgical facility is required forpreparation of the patient, staff, and medical equipment for surgery.Meanwhile, the internal bleeding continues, as well as the associatedrisk to the trauma victim.

For these reasons, it would be desirable to provide methods and systemfor identifying, targeting, and controlling of internal bleeding,preferably without the damage to surrounding or intervening tissueassociated with surgical intervention. Preferably, such methods wouldprovide hemostasis sufficient for the transport of patients to acritical care facility, where more conventional surgical and diagnostictechniques are available. Ideally, these methods and systems forproduction of coagulation would be suitable for emergency rooms, localclinics, and even paramedics in the field. It would be best if suchmethods and systems could make use of the advances in imaging andtherapeutic ultrasound technologies which have previously been appliedto focal diseases.

2. Description of the Background Art

U.S. Pat. No. 5,322,055 describes an ultrasonic clamp which coagulatestissues within a scissor-like jaw as it cuts. U.S. Pat. No. 5,013,312describes an ultrasonic scalpel having an integral bipolar electrode tocoagulate as it cuts.

U.S. Pat. No. 5,207,672 describes the use of laser energy to causecoagulative necrosis of compressed prostatic tissue. U.S. Pat. No.5,269,778 describes the use of a variable pulse width laser to penetratetissue and effect deep coagulation.

U.S. Pat. No. 5,052,395 describes an ultrasonic pulse Doppler cardiacmonitor which measures blood velocity. U.S. Pat. No. 5,152,294 describesa three-dimensional ultrasonic scanner. U.S. Pat. No. 5,186,175describes a two-dimensional ultrasonic diagnostic array. U.S. Pat. Nos.5,379,642, 5,255,682, 4,945,915, 4,155,260, and 5,050,588 are generallyrelevant.

C. Delon-Martin et al., Venous Thrombosis Generation by MeansHigh-Intensity Focused Ultrasound, Ultrasound in Medicine and Biology,21:113 (1995) describes a HIFU for sclerotherapy of superficial varicoseveins. Vein walls were specifically targeted for thermal ultrasonictherapy, leading to temporary vein occlusion.

V. Zurinski et al., Real-Time Sonography with the Linear Array ScannerMultison 400, Electromedica, 46, No. 4 (1978); R. D. Selbie et al., TheAberdeen Phased Array: A Real-Time Ultrasonic Scanner with DynamicFocus, Medical and Biological Engineering and Computing, 18:335 (May1980); O. T. von Ramm et al., Thaumascan: Design Considerations andPerformance Characteristics, Ultrasound in Medicine, 1:373 (October1974); D. Latham King, Real-Time Cross-Sectional Ultrasonic Imaging ofthe Heart Using a Linear Array Multi-Element Transducer, The Journal ofClinical Ultrasound, 1:196 (1973) are also generally relevant.

SUMMARY OF THE INVENTION

The present invention promotes the remote coagulation of blood usinghigh-intensity focused ultrasound (HIFU). In particular, the presentinvention provides methods and devices for identifying a site ofinternal bleeding, and focusing therapeutic ultrasound energy through anintervening tissue and onto the bleeding site, so as to remotely providehemostasis. Such systems and methods allow the diagnosis andstabilization of trauma victims suffering hemoperitoneum withoutresorting to invasive surgical procedures. Advantageously, the remotehemostasis of the present invention may be used as a complete therapy,or may alternatively be used to buy time for the patient to reach andreceive conventional treatment in a critical care facility.

In a first aspect, the method of the present invention comprisesidentifying a site of internal bleeding, and focusing therapeuticultrasound energy on the site. The energy is transmitted from aradiating surface and passes through an intervening tissue. The focusedenergy coagulates blood adjacent to the internal bleeding site, therebyproviding hemostasis.

As used herein "hemostasis" is defined as a temporary or permanentreduction or cessation of the release of blood from the circulatorysystem, tissues, and organs.

Preferably, the identifying step comprises Doppler imaging a section ofthe patient body with a pulsed ultrasound transducer, typically usingcolorflow imaging techniques. Additionally, the identifying steppreferably comprises elasticity imaging. As more fully described in U.S.Pat. No. 5,178,147, the full disclosure of which is incorporated hereinby reference, elasticity imaging is performed by locally displacingtissue and monitoring the tissue displacement. Elasticity imaging isparticularly well-suited or the identification of stiff coagulatedregions and unconstrained liquids such as freestanding blood.Alternatively, a contrast agent may be introduced into the blood streamand an X-ray or ultrasound angiogram made to identify the internalbleeding site. Optionally, identification relies on sensing andisolating the acoustic or other vibrational signature of a vascularbreach.

In a second aspect, the present invention provides a method comprisingidentifying a site of internal bleeding, targeting a region adjacent tothe site for therapy, and focusing therapeutic ultrasound energy on atarget within the therapy region. The ultrasound energy is again emittedfrom a radiating surface, and passes through an intervening tissue onits way to the target. Generally, an appropriate target depth is alsoselected. Preferably, the radiating surface and an ultrasound imagingtransducer array are carried within a single housing, allowing thedevice to be easily aimed towards the internal bleeding site by movingthe housing over the patient's skin in a "point-and-shoot" mode.

The focusing step of the method of the present invention generallycomprises coagulating blood at the target. In connection with thepresent invention, it has been discovered that such coagulation isapparently the result of at least three separate mechanisms. First,heating has been observed to cause thrombosis, even at relatively lowlevels above body temperature. Second, mechanical streaming of bloodcaused by the ultrasound energy, and the impact of that blood withvessel walls and other obstructions, has been observed to cause theproduction of thrombi. Third, HIFU typically produces cavitation in thefocal zone. Such cavitation can result in the production of freeradicals as a chemical by-product. Such free radicals have beenassociated with the production of thrombi. Finally, there are reasons tobelieve that other chemical changes in the blood caused by ultrasoundcan also be contributory to the production of thrombi.

In certain cases, such as vascular breaches in smaller blood vessels,hemostasis is provided by coagulating blood so as to form a plug withinthe vessel. Preferably, the therapy volume extends upstream of thevascular breach along the blood vessel, so that the plug occludes thevessel and reduces the release of blood. Alternatively, hemostasis maybe achieved by cauterizing tissue, particularly by selecting a therapyregion which encompasses an organ fracture. In certain cases, theultrasound energy may be used to weld tissues at the target, analogousto the ultrasonic cauterization of vessels produced by mechanicalultrasonic clamps.

In yet another aspect, the present invention provides a method forproducing remote hemostasis comprising identifying a site of internalbleeding, and introducing an ultrasound hemostasis enhancement agent tothe site. Therapeutic ultrasound energy is then focused from a radiatingsurface to activate the hemostasis agent adjacent to the site, theenergy passing through an intervening tissue. Optionally, the hemostasisagent foams under ultrasound energy, so as to occlude a vascular breach.Suitable foaming hemostasis agents includes perfluorocarbons,particularly those having boiling temperatures between 40° C. and 80° C.Alternatively, the hemostasis agent comprises an encapsulatedthrombus-producing agent, typically being an element from the clottingcascade. The use of such hemostasis agents will be particularlyadvantageous for providing remote hemostasis to vascular breaches ofmajor vessels, for example, in stabilizing a ruptured abdominal aneurysmwithout occluding the aorta.

An apparatus for producing remote hemostasis according to the presentinvention comprises a radiating surface which applies focusedtherapeutic ultrasound energy on a remote target, and a sensor foridentifying a site of internal bleeding. A registration mechanism iscoupled to the radiating surface and the sensor to align the target andthe internal bleeding site. Therapy for internal bleeding is therebyprovided without the need for invasive surgical procedures, even atremote locations where surgical facilities are not available.

Preferably, a mechanism is provided to allow variations in therapy depthby adjustments to the effective focal length of a radiating surface,thereby varying the distance between the radiating surface and thetarget. Ideally, the radiating surface is formed as a phased array, andthe depth varying mechanism comprises a phase controller. A phased arraycomprising an annular array is particularly preferred, allowing simpleand accurate variations in focal depths with a minimum amount of circuitcomplexity.

Optionally, the registration means comprises a mechanical linkagebetween the radiating surface and the sensor. The radiating surface andsensor may be affixed to a common structure to facilitate registrationof the target. Nonetheless, one or more degrees of freedom are oftenprovided between the sensor and radiating surface, for example, thevariable therapy depth of a phased annular array radiating surface, orthe linear and sector scan servo mechanisms which alter the radiatingsurface orientation after an imaging scan and before therapy is applied.Thus, in certain embodiments, the registration means comprises aposition indication system coupled to the radiating surface and thesensor. Where the position indication system comprises a globalpositioning system providing the complete position and orientation ofthe radiating surface, the target may be registered to the site despitethe lack of any mechanical linkage. Typically, a 3-D model of a portionof the patient body is assembled from the imaging data supplied to aprocessor by the sensor, and the target is then electronicallyregistered to the 3-D model using data provided by the positionindication system.

In another aspect, an apparatus for producing remote hemostasisaccording to the present invention comprises a pulsed ultrasound imagingtransducer and an ultrasound radiating surface which focuses therapeuticenergy at a target. A display is coupled to both the imaging transducerand to the radiating surface, so that the display indicates a relativeposition of the target and an internal bleeding site. Preferably, theradiating surface comprises a phased array to provide a variable therapydepth, while the display generally indicates any difference between theselected depth and the depth of the site.

Optionally, a structure carries the transducer and the radiatingsurface, and a translation of the structure relative to the site resultsin a repositioning of the site relative to the target on the display.Such a structure, typically comprising a housing, allows at least roughlocating of the internal bleeding site by relocating or sliding thehousing over the patient's skin. Optionally, precise positioning isprovided by a servo mechanism supporting the radiating surface from thehousing structure, or by electronic manipulation of the phased array.Alternatively, the remote hemostasis apparatus may be used as a"point-and-shoot" device, being aimed toward the target location byhand, focused to the target depth by manipulation of an annular array,and manually activated. Such a "point-and-shoot" device would beparticularly advantageous for emergency medical personnel, includingboth civilian paramedics and military field medics.

Preferably, the display will provide a Doppler colorflow image,facilitating the identification of internal bleeding. Optionally, atissue displacement mechanism is coupled to the imaging transducer,allowing the display to provide an elasticity image as described above.As well as providing indications of internal bleeding, such Dopplercolorflow images and elasticity images will also facilitate theidentification and mapping of coagulated and cauterized regions, therebyenhancing the therapy zone management of the apparatus. Optionally, acoagulation memory is coupled to the radiating surface and the displayso that the display electronically indicates coagulated regions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a high-intensity focused ultrasound (HIFU) remotehemostasis apparatus according to the principals of the presentinvention.

FIG. 2 illustrates a HIFU probe for use with the remote hemostasisapparatus of FIG. 1.

FIG. 3 is a cross-section of the HIFU probe of FIG. 2.

FIG. 4 is a cross-section of the distal end of the HIFU probe of FIG. 3,showing a membrane pressurization system which acts as a local tissuedisplacement mechanism for elasticity imaging.

FIG. 5 illustrates a control diagram for the remote hemostasis apparatusof FIG. 1.

FIG. 6 illustrates a therapy zone appropriate for providing hemostasisof an organ fracture using the remote hemostasis apparatus of FIG. 1.

FIGS. 7A-C illustrate a self-contained point-and-shoot remote hemostasisapparatus according to the principles of the present invention.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS

The present invention provides a high-intensity focused ultrasound(HIFU) system and methods for its use to provide remote hemostasis. TheHIFU apparatus of the present invention will find a wide range ofapplications for the identification and targeting of internal bleeding.The present invention will have particular applications for aneurysmsand other diseases of the vascular system. The apparatus and methods ofthe present invention will find further use in establishing hemostasisafter an invasive surgery surgical procedure. Furthermore, hemostasisand cauterization provided by the present invention may be used to denya supply of blood to certain diseased tissues, particularly tissueshaving hyperplastic diseases.

The present remote hemostasis apparatus and methods may be appliedlaparoscopically, using an intraluminal probe, minimally invasively,using an intracavity probe, or non-invasively, using an extracorporalprobe. Although such systems and methods will thus have a wide range ofapplications, the present invention will find its greatest applicationsin the stabilization of the victims of blunt trauma, either prior toconventional invasive procedures, or instead of such procedures. Themethods and apparatus of the present invention are particularlywell-suited for medical and emergency personnel who do not haveimmediate access to extensive critical care health facilities.

Referring now to FIG. 1, the remote hemostasis system 1 includes a probe10 and a controller 12. Controller 12 includes a display 14, which isused to image tissues, identify internal bleeding sites, and selectzones of a patient body for therapy. Remote hemostasis system 1 is aspecialized ultrasonic therapy system of the general type which is morefully described in application Ser. No. 08/446,503, the full disclosureof which has previously been incorporated herein by reference. Thestructure of the present system is also described in U.S. patentapplication Ser. No. 07/840,502, filed Feb. 21, 1992, and reproduced inPCT Patent Application No. PCT/US93/01551, published Sep. 2, 1993, thefull disclosures of which are also incorporated herein by reference.

As more fully explained in the application Ser. No. 08/446,503, probe 10is adapted for use as an intracavity probe, typically being used bypositioning a patient on a treatment table and transrectally insertingand positioning the treatment probe. A transducer disposed within theprobe housing images a tissue using a linear and/or sector scanningmovement of the transducer relative to the housing. The operatorgraphically selects a therapy volume, and also inputs treatmentparameters. The controller automatically linearly and angularlypositions the transducer so that the active surface is focused at thetarget tissue. The controller then activates the focused radiatingsurface of the transducer, applying therapeutic ultrasound energy to atarget within the therapy zone.

Referring now to FIG. 2, probe 10 includes a probe housing 11 having aproximal end 16, a distal end 18 and an acoustic window 20. The probehousing is shown without a membrane over window 20 for clarity. Thedistal portion of housing 10 contains a transducer member havingback-to-back active surfaces with focal geometries at a first and asecond distance from the probe housing 11, respectively (see FIG. 5). Byrotating the transducer member within the housing and energizing theradiating surfaces independently, probe 10 is capable of applying HIFUtherapy focused at a first distance 22 from housing 11 and also at asecond distance 24 from housing 11. Generally, the actual first andsecond target volumes associated with these distances will at least beadjacent, and will preferably overlap, so that ultrasonic therapy can beapplied to coagulate blood and/or cauterize tissues which lie throughoutthe volume between first distance 22 and second distance 24.Additionally, one or both of the back-to-back radiating surfacescomprise annular arrays, allowing electronic adjustments of the therapydistances, as described hereinbelow.

Referring now to FIG. 3, probe housing 11 contains a transducer member28 featuring two back-to-back therapeutic ultrasound focusing radiatingsurfaces having different focal geometries. Probe housing 11 broadlyincludes a transducer region 30 near distal end 18 and a handle region32 near proximal end 16. Probe housing 11 may be formed frompolyurethane, ABS plastic, or the like.

Transducer member 28 is disposed within an interior volume defined bytransducer region 30, but does not contact probe housing 11 in thetransducer region, being cantilevered from the handle region 32.Transducer member 28 is thus free to both rotate about the axis oftransducer region 30, and to translate axially. Window 20 providespassage for ultrasonic energy within a range of axial and angularpositions of the radiating surfaces of transducer member 28, as seen inFIG. 2. Disposed over the distal end 18 of transducer region 30 is anacoustic membrane 38.

Contained within handle region 32 of housing 11 are a transducerpositioning mechanism 34 and a reservoir 36. Positioning mechanism 34provides linear and sector scanning motion to transducer member 28relative to housing 11, and also provides position feedback tocontroller 12 (see FIG. 1). Positioning mechanism 34 allows aiming ofthe radiating surfaces towards the internal bleeding site, selectsbetween the back-to-back radiating surfaces, and also mechanically scansan ultrasonic imaging transducer array 45 attached to transducer member28. An exemplary positioning mechanism was described in application Ser.No. 07/840,502.

Referring now to FIG. 4, transducer member 28 includes a first radiatingsurface 50 having a relatively long focal length and a second radiatingsurface 52 having a relatively short focal length as compared to thelong focal length. First radiating surface 50, in turn, includes aninner region 56 and an outer region 54, while second radiating surface52 similarly includes inner and outer regions 60, 58. This separation offirst radiating surface 50 and second radiating surface 52 into innerand outer regions allows additional control over the therapy depth byvarying the relative phase of power supplied to the inner and outerregions, first and second radiating surfaces 50, 52 acting as simpleannular phased arrays. The use of annular phased arrays for controllingthe depth of therapeutic ultrasound focusing is more fully explained inco-pending U.S. patent application Ser. No. 08/333,471, the fulldisclosure of which is herein incorporated by reference. Clearly, alarger number of regions provides additional flexibility in the focaldepth.

The radiating surfaces of transducer member 28 are coupled to acousticmembrane 38 by a coupling fluid contained within transducer region 30 ofprobe housing 11. Acoustic membrane 38 is, in turn, coupled to thepatient body by direct contact against tissue in the region of acousticwindow 20. Optionally, transducer region 30 is inserted transrectally,transvaginally, transesophageally, or the like. Alternatively, couplingmembrane 38 is held against the patient's skin, either manually or usinga table clamp attached to the probe, as known in the art. Suchextracorporal coupling of the radiating surface to the tissue of thepatient body allows aiming of the radiating surfaces by repositioningprobe 10 against a different region of the patient's skin, ideally bysliding acoustic membrane 38 against the skin. Once probe 10 is roughlyin position, the servo mechanisms of transducer positioning mechanism 34may be used to precisely aim the radiating surfaces 50, 52.Alternatively, a radiating surface comprising a two-dimensional phasedarray would allow electronic aiming and focusing, analogous to theelectronic variation in therapy depth provided by an annular array.

Acoustic membrane 38 may conveniently be integrated into a local tissuedisplacement mechanism for elasticity imaging. While transducer region30 is held in coupling contact with the patient body, coupling fluidpressure P may be varied in a controlled fashion to displace the tissuewhich is adjacent to ultrasound transducer array 45. Acoustic membrane38 ideally comprises an inelastic, non-distensible, thin membrane asdescribed in application Ser. No. 08/446,503, typically being formed ofPET, polyamide, or polyethylene, preferably being less than onewavelength of ultrasonic energy in thickness. Preferably, the tissuedisplacement mechanism operates at a regular interval, usually having afrequency between 1 and 50 Hz.

Referring now to FIG. 5, a registration system 60 comprises a processor62, a memory 64, and display 14. Positioning mechanism 34 (shown in FIG.3) is located in the probe handle, and includes a rotational positioningmotor 66 and a rotational position indicator 68. As described above,imaging transducer 45 provides an image of a portion of a patient bodyhaving an internal bleeding site, typically using pulsed Dopplercolorflow imaging, elasticity imaging, an angiogram, or the like.Display 14 provides an image of the internal bleeding site.

As shown in FIG. 5, a blood vessel 70 having a vascular breach 72 hasreleased blood into the abdominal cavity. The blood forms a low pressurepool 74, which has been identified using display 14. Typically, imagingtransducer 45 sweeps a section of the patient body to produce the image,either mechanically sweeping using motor 66, or electronically sweepingby use of a phased array.

The operator selects a treatment volume, for example, by manipulation ofa trackball, a mouse, or the like. As shown, a deep therapy volume 76and a shallow therapy volume 78 have been defined. Such therapy volumes,targeting both the blood within the vessel and the vessel wall itself,promotes the formation of a plug to occlude the vessel and prevent bloodleaking from vascular breach 72.

Imaging transducer 45 and radiating surfaces 50, 52 are supported ontransducer member 28. This mechanical connection facilitates thealigning of a selected treatment target within a therapy volume to theinternal bleeding site. Nonetheless, transducer member 28 will rotatebetween imaging and therapy, particularly when therapy is provided byradiating surface 50. Thus, processor 62 manipulates transducer member28 using rotational motor 68, and receives feedback from positionindicator 68 to register the treatment target to the therapy zoneadjacent to the internal bleeding site. Preferably, as individualtargets are coagulated, coagulation memory 64 maps that information ondisplay 14, allowing efficient therapy zone management.

Referring now to FIG. 6, an organ 80 having an organ fracture 82 oozesblood from a large number of small vessels 84, resulting in a pool ofblood 86 within the abdominal cavity. A therapy volume 88 is selectedwhich not only coagulates blood, but also cauterizes the soft tissue ofthe organ in the area adjacent to the organ fracture. Thus, perfuseorgans such as the liver and kidneys may be selectively cauterized toprovide acoustic hemostasis without resorting to occlusion of amultiplicity of individual blood vessels.

Referring now to FIGS. 7A-C, a point-and-shoot remote hemostasis probe90 comprises a radiating surface in the form of an annular array 92.Annular array 90 applies therapies at depths ranging up to 3/2 the arrayaperture, the aperture typically being between two and ten inches.Annular array 92 is carried by a housing 94, which also carries amechanically oscillating linear imaging transducer array 96. The imagingtransducer and a global positioning system 98 provide information to aprocessor, which assembles a 3-D model of an internal region of a patentbody. The model is displayed in real time on a screen 100, with themodel orientation updated to reflect movement of probe 90 from datasupplied by global positioning system 98.

Point-and-shoot probe 90 is particularly advantageous for field medicaltreatment, allowing a paramedic to identify a site of internal bleeding,position the probe to target the site, select a proper therapy depth,and apply therapy to provide hemostasis before transporting the patient.

Although the specific embodiments have been described in detail, variousalternatives, modifications, and equivalents, may be used. Thus, theabove description should not be taken as limiting the scope of theinvention, which is instead defined solely by the appended claims.

What is claimed is:
 1. An apparatus for producing remote hemostasiscomprising:a radiating surface which applies focused therapeuticultrasound energy to a target volume, the target volume being separatedfrom the radiating surface by a therapy depth to produce remotehemostasis; a sensor which identifies a site of internal bleeding; and aregistration mechanism coupled to the sensor and the radiating surfaceto align the target volume and the site.
 2. A remote hemostasisapparatus as claimed in claim 1, further comprising a therapy depthvarying mechanism coupled to the radiating surface.
 3. A remotehemostasis apparatus as claimed in claim 2, wherein the radiatingsurface comprises a phased array, and wherein the depth varyingmechanism comprises a phase controller.
 4. A remote hemostasis apparatusas claimed in claim 3, wherein the phased array comprises an annulararray.
 5. A remote hemostasis apparatus as claimed in claim 1, whereinthe sensor comprises a pulsed ultrasound imaging transducer.
 6. A remotehemostasis apparatus as claimed in claim 5, further comprising a displaycoupled to the imaging transducer for providing Doppler imaging of thesite.
 7. A remote hemostasis apparatus as claimed in claim 5, whereinthe sensor further comprises a tissue displacement mechanism, theapparatus further comprising a elasticity imaging display coupled to thesensor.
 8. A remote hemostasis apparatus as claimed in claim 1, furthercomprising a processor coupled to the sensor for isolating a vibrationalsignal of vascular breaches.
 9. A remote hemostasis apparatus as claimedin claim 1, wherein the sensor comprises a display for providingangiographic imaging of the site.
 10. A remote hemostasis apparatus asclaimed in claim 1, wherein the registration mechanism comprises amechanical linkage between the radiating surface and the sensor.
 11. Aremote hemostasis apparatus as claimed in 1, wherein the registrationmechanism comprises a position indication system coupled to at least oneof the radiating surface and the sensor.
 12. An apparatus for producingremote hemostasis comprising:a pulsed ultrasound imaging transducerwhich identifies a site of internal bleeding; an ultrasound radiatingsurface which focuses therapeutic energy at a target volume to produceremote hemostasis; and a display coupled to the imaging transducer andto the radiating surface, the display indicating a relative position ofthe target volume and the internal bleeding site.
 13. A remotehemostasis apparatus as claimed in claim 12, wherein the radiatingsurface comprises a phased array having a selectable therapy depthbetween the radiating surface and the target volume, and wherein thedisplay indicates any difference in depth between the selected therapydepth and the site.
 14. A remote hemostasis apparatus as claimed inclaim 12, further comprising a structure which carries the imagingtransducer and the radiating surface, wherein a translation of thestructure relative to the site causes the display to indicaterepositioning of the site relative to the target volume.
 15. A remotehemostasis apparatus as claimed in claim 12, wherein the displaycomprises a display for providing Doppler colorflow imaging.
 16. Aremote hemostasis apparatus as claimed in claim 15 further comprisingmeans for providing feedback on regions of coagulated blood.
 17. Aremote hemostasis apparatus as claimed in claim 12, further comprising atissue displacement mechanism coupled to the imaging transducer, whereinthe display provides an elasticity image.
 18. A remote hemostasisapparatus as claimed in claim 17 further comprising means for providingfeedback on both regions of coagulated blood and regions of cauterizedtissue.
 19. A remote hemostasis apparatus as claimed in claim 12,further comprising a coagulation memory coupled to the radiating surfaceand the display so that the display indicates coagulated regions.